Composition comprising niacinamide and picolinamide

ABSTRACT

The present invention relates to a topical composition and more particularly a topical composition for antimicrobial benefit. According to the present invention there is provided a topical composition comprising Niacinamide and picolinamide wherein the molar ratio of Niacinamide to picolinamide is from 1:20 to 20:1.

TECHNICAL FIELD

The present invention relates to a topical composition and moreparticularly a topical composition for antimicrobial benefit.

BACKGROUND OF THE INVENTION

People try to take good care of the external surface of their bodies.Specific skin related issues that people care about include good skinhealth free of infections, good skin tone and skin hygiene. Skin hygieneis generally achieved by keeping them free of infections. One way totackle infections is to treat them with antimicrobials after theinfection has set in. Another approach is to leave a minimal amount ofantimicrobial active on the surface so that any invading microorganismis killed or inactivated to minimize spread of diseases. Yet anotherapproach is improving the innate immunity of the desired surface. Someof the bacteria like E. coli, S aureus are generally exists on the skin.These bacteria does not have any pathogenic effect per se on the skin.However when this goes inside the body through ingestion, they inducestheir pathogenic effect. Therefore keeping the external surface of thebody e.g. hand, scalp free of this bacteria helps in achieving thedesired hygiene.

AMPs form an integral part of the skin's own defense system. AMPs wereinitially discovered in insects and in animals and ever since theirinitial discovery AMPs are regarded as promising antimicrobials. AMPsare ubiquitous in nature and they typically exhibit a broad spectrum ofactivity against invading bacteria, fungi, enveloped viruses andparasites (Braff and Gallo, 2006. AMPs are generally short peptides andin humans about 90 different AMPs are reported to be present. AMPs ingeneral have two major physical features and they are—a) cationic chargeand b) a significant proportion of hydrophobic residues. The cationiccharge of the AMPs promotes selectivity for negatively charged microbialcytoplasmic membranes whereas the hydrophobicity facilitatesinteractions with the cell membrane of the microbial species.

Niacinamide is known in the art for inducing AMP generation on the skinthereby providing antimicrobial benefit.

WO 2015/172801 (Unilever, 2015) discloses a new use of niacinamide fortriggering generation of AMPs (antimicrobial peptides) on skin. This hasapplication in improving the immunity of skin, scalp and oral cavityagainst attack by microorganisms.

The present inventors have been working to provide hygiene benefits toconsumers through the route of enhancing the AMP levels in the skin.

It is therefore an object of the present invention to provide anantimicrobial composition.

It is another object of the present invention to provide anantimicrobial composition for through the route of enhancing the AMPlevels in the skin.

It is yet another object of the present invention to provide anantimicrobial composition for leave-on application, which hasantimicrobial efficacy for long time.

The present inventors while working extensively on this havesurprisingly found that a composition comprising Niacinamide andpicolinamide in a particular ratio provides significantly betterantimicrobial benefit by inducing AMP when compared to Niacinamidealone, thereby satisfies one or more of the above said objects.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a topical compositioncomprising Niacinamide and picolinamide wherein the molar ratio ofNiacinamide to picolinamide is from 1:20 to 20:1.

In a second aspect, the present invention provides a method of cleaningor disinfecting a surface comprising the steps of applying a compositionof the first aspect on to said surface.

In a third aspect the present invention provides a use of a compositioncomprising Niacinamide and picolinamide for improved antimicrobialbenefit.

In a fourth aspect the present invention provides a use of a compositioncomprising Niacinamide and picolinamide for inducing secretion ofanti-microbial peptides (AMPs) when applied on an external surface ofthe human body.

Any feature of one aspect of the present invention may be utilized inany other aspect of the invention. The word “comprising” is intended tomean “including” but not necessarily “consisting of” or “composed of.”In other words, the listed steps or options need not be exhaustive.Except in the operating and comparative examples, or where otherwiseexplicitly indicated, all numbers in this description indicating amountsof material or conditions of reaction, physical properties of materialsand/or use are to be understood as modified by the word “about”.Numerical ranges expressed in the format “from x to y” are understood toinclude x and y. When for a specific feature multiple preferred rangesare described in the format “from x to y”, it is understood that allranges combining the different endpoints are also contemplated.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a topical composition comprisingNiacinamide and picolinamide wherein the molar ratio of Niacinamide topicolinamide is from 1:20 to 20:1.

One of the component of the composition of the present invention isNiacinamide. Niacinamide is also known as nicotinamide and aspyridine-3-carboxamide is the active, water soluble form of vitamin B3.It is essential to the coenzymes NADH and NADPH and therefore for over200 enzymatic reactions in the body including ATP formation.

Another essential component of the composition of the present inventionis picolinamide. Nicotinamide, a pyridine 3-carboxamide has 2 otherpositional isomers by substitution at 2, and 4 position of the pyridinering, picolinamide (pyridine 2-carboxamide) and isonicotinamide(pyridine 4-carboxamide) respectively.

The molar ratio of niacinamide to picolinamide is from 1:20 to 20:1,preferably from 1:15 to 15:1, more preferably from 1:10 to 10:1, furthermore preferably from 1:8 to 8:1, even more preferably 1:5 to 5:1 andmost preferably from 1:2 to 2:1. The present inventors have found that,niacinamide and picolinamide at this particular ratios providesynergistic antimicrobial benefit in terms of AMP generation. Therefore,the composition preferably comprises a synergistic combination ofniacinamide and picolinamide.

There is no upper limit of the amount of niacinamide in the composition.However, preferably niacinamide is present in the composition in anamount from 0.1 to 20%, more preferably from 1 to 10%, further morepreferably from 1 to 5% and most preferably from 1 to 3% by weight ofthe composition.

Additionally, there is also no upper limit of the amount of picolinamidein the composition. However, preferably picolinamide is present in thecomposition in an amount from 0.1 to 20%, more preferably from 1 to 10%,further more preferably from 1 to 5% and most preferably from 1 to 3% byweight of the composition.

The composition of the present invention preferably comprises acosmetically acceptable base.

The cosmetically acceptable base is preferably a cream, lotion, gel oremulsion.

Personal care compositions (leave-on) may be prepared using differentcosmetically acceptable emulsifying or non-emulsifying systems andvehicles. A highly suitable base is a cream. Vanishing creams areespecially preferred. Vanishing cream bases generally comprise 5 to 25%fatty acid and 0.1 to 10% soap. Vanishing cream base gives a highlyappreciated matty feel to the skin. C12 to C20 fatty acids areespecially preferred in vanishing cream bases, further more preferredbeing C14 to C18 fatty acids. The most preferred fatty acid is stearicacid. The fatty acid in the composition is more preferably present in anamount in the range of 5 to 20% by weight of the composition. Soaps inthe vanishing cream base include alkali metal salt of fatty acids, likesodium or potassium salts, most preferred being potassium stearate. Thesoap in the vanishing cream base is generally present in an amount inthe range of 0.1 to 10%, more preferably 0.1 to 3% by weight of thecomposition. Generally, the vanishing cream base in personal carecompositions is prepared by taking a desired amount of total fattymatter and mixing with potassium hydroxide in desired amounts. The soapis usually formed insitu during the mixing.

An especially suitable cosmetically acceptable base is one whichcomprises a water-in-oil emulsion comprising silicone oils as thecontinuous phase. The water in oil emulsions preferably comprise across-linked silicone elastomer blend.

Inclusion of silicone elastomer blend in a water-in-oil emulsion may beused as the cosmetically acceptable base for preparing the compositionsof the present invention. While silicone fluids may be used, siliconeelastomers which are cross-linked, are especially preferred. In contrastto silicone fluid polymers, the physical properties of elastomers aretypically dependent on the number of cross-linkages, rather thanmolecular weight. The ability of silicone elastomers to swell makes themideal thickeners for oil phases. The elastomers have a very smooth andsoft feel when applied to skin or hair. They can also be used asdelivery agents for fragrances, vitamins and other additives in cosmeticcompositions.

Suitable silicone elastomer blends or gels which are commerciallyavailable and suitable for inclusion in the composition of the inventionand found to provide the enhanced stability are: Dow Corning® EL-8051 INSilicone Organic Elastomer Blend [INCI Name: Isodecyl Neopentanoate(and) Dimethicone/Bis Isobutyl PPG-20 Crosspolymer]; EL-8050 [INCI Name:Isododecane (and) Dimethicone/Bis-Isobutyl PPG 20 Crosspolymer] DC 9040,DC9041, DC9045 (Dimethicone crosspolymer); DC 9506, 9509 (Dimethiconevinyl dimethicone crosspolymer); Shin-Etsu KSG-15, KSG-16, KSG-17(Dimethicone vinyl dimethicone crosspolymer). It is further preferredthat the composition comprises 5 to 50% silicone elastomer by weight ofthe composition.

The composition of the present invention may optionally comprises ofskin lightening agents e.g. aloe extract, ammonium lactate, arbutin,azelaic acid, kojic acid, butyl hydroxy anisole, butyl hydroxy toluene,citrate esters, 3 diphenyl propane derivatives, 2,5 dihydroxybenzoicacid and its derivatives, ellagic acid, fennel extract, glucopyranosyl-1-ascorbate, gluconic acid, glycolic acid, green tea extract,hydroquinone, 4 hydroxyanisole and its derivatives, 4-hydroxy benzoicacid derivatives, hydroxycaprylic acid, lemon extract, linoleic acid,magnesium ascorbyl phosphate, mulberry root extract, 2,4 resorcinolderivatives, 3,5 resorcinol derivatives, salicylic acid, vitamins likevitamin B6, vitamin B12, vitamin C, vitamin A, a dicarboxylic acid,resorcinol derivatives, hydroxycarboxylic acid like lactic acid andtheir salts e.g. sodium lactate, and mixtures thereof.

Additionally, though not preferred, the composition may have sunscreen.Any sunscreen that can be suitably used with the base may be added.Both, UVA and UVB sunscreens may preferably be added.

The composition of the invention may preferably comprises a UV-Asunscreen which is a dibenzoylmethane or its derivatives. Preferreddibenzoylmethane derivatives are selected from4-tert-butyl-4′-methoxydibenzoylmethane, 2-methyldibenzoylmethane,4-methyl-dibenzoylmethane, 4-isopropyldibenzoyl-methane,4-tert-butyldibenzoylmethane, 2,4-dimethyldibenzoylmethane,2,5-dimethyldibenzoylmethane, 4,4′-diisopropyl-10 dibenzoylmethane,2-methyl-5-isopropyl-4′-methoxydibenzoylmethane,2-methyl-5-tert-butyl-4′-methoxy-dibenzoyl methane,2,4-dimethyl-4′-methoxy dibenzoylmethane or2,6-dimethyl-4-tert-butyl-4′-methoxy-dibenzoylmethane. The mostpreferred dibenzoylmethane derivative is4-tert.-butyl-4′-methoxydibenzoylmethane. The composition of theinvention preferably comprises 0.1 to 10%, more preferably 0.2 to 5%,further more preferably 0.4 to 3%, by weight dibenzoylmethane or aderivative thereof based on total weight of the composition andincluding all ranges subsumed therein.

The composition may also preferably comprises a UV-B organic sunscreenselected from the class of cinnamic acid, salicylic acid, diphenylacrylic acid and derivatives thereof. Illustrative non-limiting exampleof UV-B sunscreens which are commercially available and useful forinclusion in the composition of the invention are Octisalate™,Homosalate™, NeoHelipan™, Octocrylene™, Oxybenzone™ or Parsol MCX™. TheUV-B sunscreen is most preferably 2-ethyl-hexyl-4-methoxy cinnamatewhich is commercially available as Parsol MCX. The UV-B organicsunscreen is preferably included in 0.1 to 10%, more preferably 0.1 to7% by weight of the composition. It has been observed that presence ofan organic UV-B sunscreen like 2-ethyl-hexyl-4-methoxy cinnamate causesfurther rapid degradation of the UV-A dibenzoylmethane sunscreen in thepresence of UV radiation. The presence of the rosmarinic acid estercompound is found to be very efficacious in stabilizing the compositioneven when UV-B sunscreens are present.

Useful inorganic sun-blocks are also preferably used in the presentinvention. These include, for example, zinc oxide, iron oxide, silica,such as fumed silica, and titanium dioxide.

Preservatives can also be added into the compositions to protect againstthe growth of potentially harmful microorganisms. Suitable traditionalpreservatives for compositions of this invention are alkyl esters ofpara-hydroxybenzoic acid. Other preservatives which have more recentlycome into use include hydantoin derivatives, propionate salts, and avariety of quaternary ammonium compounds. Particularly preferredpreservatives are phenoxyethanol, methyl paraben, propyl paraben,imidazolidinyl urea, sodium dehydroacetate, benzyl alcohol, alkane diolsmost preferably 1,2-octane diol and phenoxyethanol. The preservativesshould be selected having regard for the use of the composition andpossible incompatibility between the preservatives and otheringredients. Preservatives are preferably employed in amounts rangingfrom 0.01% to 2% by weight of the composition.

A variety of other optional materials may be formulated into thecompositions. These may include: antimicrobials such as2-hydroxy-4,2′,4′-trichlorodiphenylether (triclosan),2,6-dimethyl-4-hydroxychlorobenzene, and 3,4,4′-trichlorocarbanilide;scrub and exfoliating particles such as polyethylene and silica oralumina; cooling agents such as menthol; skin calming agents such asaloe vera; and colorants.

In addition, the compositions may further include 0 to 10% by weight ofopacifiers and pearlizers such as ethylene glycol distearate, titaniumdioxide or Lytron® 621 (Styrene/Acrylate copolymer); all of which areuseful in enhancing the appearance or properties of the product.

Diluents other than water can include liquid or solid emollients,solvents, humectants, thickeners and powders. Examples of each of thesetypes of vehicle, which can be used singly or as mixtures of one or morevehicles, are as follows:

Emollients, such as stearyl alcohol, glyceryl monoricinoleate, mink oil,cetyl alcohol, isopropyl isostearate, stearic acid, isobutyl palmitate,isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate,decyl oleate, octadecan-2-ol, isocetyl alcohol, eicosanyl alcohol,behenyl alcohol, cetyl palmitate, silicone oils such asdimethylpolysiloxane, di-n-butyl sebacate, isopropyl myristate,isopropyl palmitate, isopropyl stearate, butyl stearate, polyethyleneglycol, triethylene glycol, lanolin, cocoa butter, corn oil, cotton seedoil, olive oil, palm kernel oil, rape seed oil, safflower seed oil,evening primrose oil, soybean oil, sunflower seed oil, avocado oil,sesame seed oil, coconut oil, arachis oil, castor oil, acetylatedlanolin alcohols, petroleum jelly, mineral oil, butyl myristate,isostearic acid, palmitic acid, isopropyl linoleate, lauryl lactate,myristyl lactate, decyl oleate, myristyl myristate;

Solvents, such as ethyl alcohol, isopropanol, acetone, ethylene glycolmonoethyl ether, diethylene glycol monobutyl ether, diethylene glycolmonoethyl ether;

Advantageously, active agents other than skin conditioning agentsdefined above may be added to the composition. These active ingredientsmay be advantageously selected from bactericides, vitamins, anti-acneactives; anti-wrinkle, anti-skin atrophy and skin repair actives; skinbarrier repair actives; non-steroidal cosmetic soothing actives;artificial tanning agents and accelerators; skin lightening actives;sunscreen actives; sebum stimulators; sebum inhibitors; anti-oxidants;protease inhibitors; skin tightening agents; anti-itch ingredients; hairgrowth inhibitors; 5-alpha reductase inhibitors; desquamating enzymeenhancers; anti-glycation agents; or mixtures thereof; and the like.

These active agents may be selected from water-soluble active agents,oil soluble active agents, pharmaceutically acceptable salts andmixtures thereof. The term “active agent” as used herein, means personalcare actives which can be used to deliver a benefit to the skin and/orhair and which generally are not used to confer a skin conditioningbenefit, such are delivered by emollients as defined above. The term“safe and effective amount” as used herein, means an amount of activeagent high enough to modify the condition to be treated or to deliverthe desired skin care benefit, but low enough to avoid serious sideeffects. The term “benefit,” as used herein, means the therapeutic,prophylactic, and/or chronic benefits associated with treating aparticular condition with one or more of the active agents describedherein. What is a safe and effective amount of the active agent(s) willvary with the specific active agent, the ability of the active topenetrate through the skin, the age, health condition, and skincondition of the user, and other like factors.

Powders, such as chalk, talc, fullers earth, kaolin, starch, gums,colloidal silica sodium polyacrylate, tetra alkyl and/or trialkyl arylammonium smectites, chemically modified magnesium aluminium silicate,organically modified montmorillonite clay, hydrated aluminium silicate,fumed silica, carboxyvinyl polymer, sodium carboxymethyl cellulose,ethylene glycol monostearate.

The cosmetically acceptable base is usually from 10 to 99.9%, preferablyfrom 50 to 99% by weight of the composition, and can, in the absence ofother personal care adjuncts, form the balance of the composition.

The composition of the invention may preferably comprises a conventionaldeodorant base as the cosmetically acceptable carrier. By a deodorant ismeant a product in the stick, roll-on, or propellant medium which isused for personal deodorant benefit e.g. application in the under-armarea which may or may not contain anti-perspirant actives.

Deodorant compositions can generally be in the form of firm solids, softsolids, gels, creams, and liquids and are dispensed using applicatorsappropriate to the physical characteristics of the composition.Deodorant compositions which are delivered through roll-ons generallycomprise a liquid carrier. Such liquid carrier can be hydrophobic orcomprise a mixture of both hydrophilic and hydrophobic liquids. They maybe in the form of an emulsion or a microemulsion. The liquid carrier ormixture of carriers often constitutes from 30 to 95% by weight of thecomposition and in many instances from 40 to 80%. Hydrophobic liquidcarriers commonly can comprise one or more materials selected within thechemical classes of siloxanes, hydrocarbons, branched aliphaticalcohols, esters and ethers that have a melting point not higher than25° C. and a boiling point of at least 100° C. Hydrophilic carrierliquids that can be employed in compositions herein commonly comprisewater and/or a mono or polyhydric alcohol or water-miscible homologue.Monohydric alcohols often are short chain, by which is meant that theycontain up to 6 carbons, and in practice is most often ethanol orsometimes iso-propanol. Polyhydric alcohols commonly comprise ethyleneor propylene glycol, or a homologue can be employed such as diethyleneglycol. Other than this suitable other vehicle and component used fordeodorant composition can be added.

When the composition is in the form of a hand sanitizer composition thecosmetically acceptable base may comprises of alcohol and water. Themost preferred alcohols are ethyl alcohol and isopropyl alcohol. Even amixture of two or more alcohol can preferably be used in the handsanitizer composition. The amount of alcohol preferably in the range of50 to 95%, more preferably 60 to 80% and most preferably 65 to 80% byweight of the hand sanitizer composition.

The compositions of the present invention can comprise a wide range ofother optional components. The CTFA Personal care Ingredient Handbook,Second Edition, 1992, which is incorporated by reference herein in itsentirety, describes a wide variety of non-limiting personal care andpharmaceutical ingredients commonly used in the skin care industry,which are suitable for use in the compositions of the present invention.Examples include: antioxidants, binders, biological additives, bufferingagents, colorants, thickeners, polymers, astringents, fragrance,humectants, opacifying agents, conditioners, pH adjusters, naturalextracts, essential oils, skin sensates, skin soothing agents, and skinhealing agents.

The composition of the present invention may also comprises one or moreof the following ingredients e.g. benzethonium chloride (BEC),benzalkonium chloride (BKC), chloroxylenol, zinc pyrithione (ZPT),creatine and creatinine.

Leave-on composition preferably means those composition which is notrequired to be removed from the human body after the application of thecomposition e.g. skin cream, body lotion, hand sanitizer, deodorantsetc.

Wash-off composition preferably means those composition which isintended/required to be removed from the body by washing with solventpreferably water after the application of the composition e.g. hand washcomposition, face wash composition etc.

The present invention also discloses a method of cleaning ordisinfecting a surface comprising the steps of applying a compositionaccording to the invention on to said surface in case of a leave-oncomposition. This method optionally comprises an additional step of atleast partially removing the composition from the surface if it is inthe form of a wash-off composition. Preferably, the step of at leastpartially removing the composition is carried out less than 5 minutesafter the step of applying the composition on the substrate. Preferably,the method is non-therapeutic.

The present invention also discloses a use of a composition of thepresent invention as disclosed above for improved antimicrobial benefit.Improved antimicrobial benefit preferably means after application of thecomposition of the present invention the residual microbes on thesurface is significantly less. Therefore the composition of the presentinvention able to provide prolonged/long-lasting antimicrobial benefits.

The present invention also provides use of a composition comprisingNiacinamide and picolinamide for inducing secretion of anti-microbialpeptides (AMPs) when applied on an external surface of the human body.

The composition comprising niacinamide and picolinamide for use in thepresent invention preferably induces secretion of AMPs fromkeratinocytes. The AMPs thus secreted provides for improving theimmunity of the external surface of the human body. The external surfaceincludes skin, scalp or oral cavity.

It has been found by way of the present invention that a combination ofniacinamide and picolinamide activates keratinocytes, which are themajor cells in the skin epidermis to provide the benefits of the presentinvention viz. inducing secretion of anti-microbial peptides (AMPs).This causes to boost protection shield against germs. The compositioncomprising niacinamide and picolinamide therefore provides protectionfor the body against infections by boosting the body's own defence. Inother words, the active primes the body surface for germ protection. Theadvantage of this is that it provides long-lasting protection e.g. up to24 hours of protection against germs.

The use of the composition of the present invention may preferably forhand hygiene.

The preferred intended use of the composition of the present inventionis non-therapeutic and/or cosmetic.

The present invention also discloses the use of the composition for handhygiene.

Consequently, the present invention also provides use of a combinationof nicotinamide and picolinamide in a composition comprising acosmetically acceptable base for inducing the secretion ofanti-microbial peptides. Preferably, the invention provides such use ofa synergistic combination of nicotinamide and picolinamide. Thus, theinvention preferably provides use of a combination of nicotinamide andpicolinamide in a composition comprising a cosmetically acceptable basefor synergistically inducing the secretion of anti-microbial peptides.The preferences with regard to the composition of the present inventionapply equally to this use according to the invention.

The present invention now will be demonstrated by way of followingnon-limiting examples.

EXAMPLES

Preparation of the Composition of the Present Invention:

As an example a hand sanitizer composition was prepared as per Table 1,using the method known in the art:

TABLE 1 Ingredients Wt % Ethyl Alcohol 62.000 Isopropyl Alcohol 3.000Niacinamide 2.500 Picolinamide 2.500 Glycerin 1.000 Perfume 0.075Aminomethyl Propanol 0.147 Tocopheryl Acetate 0.050 Tetrasodium EDTA0.005 Water To 100

Furthermore, a roll-on deodorant composition was also prepared as perTable 2 using the method known in the art:

TABLE 2 Ingredients Wt % Niacinamide 2.50 Picolinamide 2.50 Sunflowerseed oil 4.00 Glycerin 4.00 Ethoxylated alcohol C18/E2 2.60 Ethoxylatedalcohol C18/E20 0.60 2-Phenoxyethanol 0.40 3-iodo-2-propynyl butylcarbamate, PEG laurate and 0.07 PEG dilaurate Water To 100

In-Vitro Experiment with Combination of Niacinamide and Picolinamide asPer the Present Invention for Generation of AMP (Psoriasin):

The experiment was done using the following protocol:

Step 1: Human neonatal primary skin keratinocyte (NHEK) cells wasobtained from Lonza®. The experiment was done with the above-mentionedcells with passage between 3 and 4. Then, the cells were seeded (35,000cells/well) in 24 well plate with keratinocyte growth media (KGM)obtained from Invitrogen®. The plate was then incubated at 37±2° C. in aCO₂ incubator for 48 hours.

Step 2: After 48 hours of incubation, cell differentiation was inducedby replacing media with fresh KGM supplemented with 2 mM calciumchloride solution. This was then followed by incubation at 37±2° C. in aCO₂ incubator for 48 hours.

Step 3: After that, the cells were treated with different concentrationof Niacinamide and picolinamide and their combination at variousconcentration as per following Table 3 with keratinocyte growth mediasupplemented with 2 mM calcium chloride solution:

TABLE 3 Example No. Treatment A Control (without Niacinamide and/orpicolinamide) B 5 mM Niacinamide C 10 mM Niacinamide D 5 mM picolinamideE 10 mM picolinamide 1 10 mM Niacinamide + 10 mM picolinamide 2 5 mMNiacinamide + 10 mM picolinamide 3 10 mM Niacinamide + 5 mM picolinamide

Step 4: After the above treatment, cells were again incubated at 37±2°C. in a CO₂ incubator for 72 hours

Step 5: After 72 h of incubation, cell culture supernatant from eachwell was collected in a sterile tube. The samples were then stored at−80° C. until used for testing psoriasin secretion by standard ELISAtechnique using psoriasin ELISA kit obtained from Circulx® (No:CY-8073). In the current experiment, psoriasin was used as a marker forAMP.

Step 6: The ELISA method was performed by using 100 μL of cell culturesupernatant from each sample. The data is expressed in terms of foldchange over control (without Niacinamide and/or picolinamide, ExampleA).

The results are summarized below in Table 4:

TABLE 4 Example No. Fold change in psoriasin secretion SD A 1   0 B 1.80.26 C 3.3 0.17 D 3.5 0.03 E 3.8 0.68 1 12.8  0.81 2 9.4 0.93 3 12.1 1.22

From the above table it is evident that the compositions that are withinthe scope of the present invention (Examples 1 to 3) provides muchbetter fold change in psoriasin (AMP) secretion than the controlexamples (Examples B to E). It is also noted that Example B (5 mMniacinamide) and Example E (10 mM picolinamide) when combined together(Example 2) provides synergistic benefit in AMP generation. Thesynergistic effect is also observed for Example 1 (combination ofExample C and Example E) and Example 3 (combination of Example C andExample D).

Therefore, from the above description it is clear that by way of presentinvention, it is now possible to provide a composition for improvedantimicrobial benefit by enhancement in the generation of AMP.

The invention claimed is:
 1. A topical composition comprisingniacinamide and picolinamide wherein the molar ratio of niacinamide topicolinamide is from 1:5 to 5:1 to provide an antimicrobial benefit whenapplied on an external surface of a human body.
 2. A composition asclaimed in claim 1 wherein the molar ratio of niacinamide topicolinamide is from 1:2 to 2:1.
 3. A composition according to claim 1further comprising a cosmetically accepted base.
 4. A compositionaccording to claim 1 comprising a skin benefit agent.
 5. A compositionaccording to claim 1 in the form of a leave-on composition.
 6. Acomposition according to claim 1 is in the form of a wash-offcomposition.
 7. A composition as claimed in claim 5 wherein saidleave-on composition includes lotion, cream, deodorant, hand sanitizerand body spray.
 8. A method of disinfecting a surface comprising thesteps of applying a composition as claimed in claim 1 on to saidsurface.
 9. A method as claimed in claim 8 wherein the composition is inthe form of a wash-off composition and wherein the method comprises anadditional step of at least partially removing the composition.
 10. Amethod as claimed in claim 9 wherein the step of at least partiallyremoving the composition is carried out in less than 5 minutes after thestep of applying the composition on a substrate.
 11. A method forinducing secretion of anti-microbial peptides (AMPs) when applied on anexternal surface of the human body using the composition of claim
 1. 12.The method as claimed in claim 11, wherein the method induces secretionof anti-microbial peptides (AMPs) from keratinocytes.